trying the famous IU Diet (TW CALORIES/ED)

IU is a famous kpop soloist and one of the things shes most famous for is her diet called the 'IU Diet" which is basically

One apple for breakfast,

one sweet potatoes for lunch,

and a protein shake for dinner.

This is basically eating 700-1,200 calories which is super low comparing that a normal person eats around 1,800+ calories a day.

I obviously am not gonna actually stick to it for a long time but im gonna do this diet for a week, including cardio workout. IU said that when she did this diet, it made her lose 4.5kg in a week. I wanna lose a few pounds so im trying this for a week while doing exercise and see if theres a difference.